CFA Continuous Flight Auger Piling – GEO CIV

CFA Continuous Flight Auger Piling

This piling system is fast and economical. It has no vibration and limited noise levels.  However, it does have some limiting features.

Positive Features

  • High production levels are attainable in suitable soil conditions
  • The system is economical in suitable soil profiles
  • Noise levels are low and limited to the engine noise of the piling rigs
  • There is no vibration associated with CFA piles

Other Considerations

  • In sandy soils below the water-table there is a reduction in soil strength in the immediate vicinity of the pile due to the drilling operation.  As a result of this, the load / deflection performance of a CFA pile is inferior to that of a driven pile
  • Soil falling off the flight can contaminate the concrete / grout of the pile shaft
  • CFA piles have to be cast to ground level.  This results in waste of concrete and excess trimming if there are deep cut-off levels
  • There is very limited indication of soil strength during the drilling operation

The maximum depth of CFA piles is 30 metres at present and the recommended maximum rake 1:10.